messages: require.js messages

* Refactors the messages/add template to use require.js.
* Loads jQuery UI modules individually.
* Fixes the jquery timepicker addon shim.
* Moves boostrap.js back into the jquery bundle (because `ui/button` shouldn't be loaded by default anymore)

@kneczaj some of the answers for #2039 are here, I hope.

**Screenshots**

![write a message - atlantis institute of fictive science 2014-08-06 09-00-28](https://cloud.githubusercontent.com/assets/1388/3823313/8fb3af50-1d37-11e4-8708-60810f889107.png)

![write a message - atlantis institute of fictive science 2014-08-06 09-00-59](https://cloud.githubusercontent.com/assets/1388/3823314/8fd8e716-1d37-11e4-9e29-5b82720c6019.png)
Can you create a separated stylesheets bundle for this module?